Don't copy the track and slide it around, DOUBLE it. Record it twice onto 2 separate tracks. The subtle difference between performances will make it more huge than copying the same track and hacking it up - you won't have phasing problems and you'll be much happier with the result IMHO.
I like to leave one in the center, fairly dry. Pan the second slightly off center and add some reverb, a hair of delay, and roll off any lows. Keep the volume down on the second track - it shouldn't stand out, just enhance the first.